Questions tagged [star-formation]

Questions related to the physical processes involved in or to the observations of the process of forming a star.

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Stars readjusting themselves in the sky [duplicate]

I had a meeting in the evening and thought of grabbing a snack before that. I stepped out of the office along with a colleague. He was on his phone and I was simply staring at the sky wishing it would ...
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Do stars come on like LEDs or wick lamps? [duplicate]

Is stellar ignition an instantaneous thing - before, dark, after, shining brightly - or more of a process over time? In fusion research 'ignition' appears to be an event, but maybe in a protostar it ...
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What is the most mass that matter likely to form?

If we plot graph between accumulate of forming mass (y-axis) and mass (x-axis), where is the maximum ? There is a story how I get this question. It start when I think about question "Is our sun is ...
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What is the lyman-werner background?

I've seen several papers that discuss the Lyman-Werner Background (LWB) when modeling star and galaxy formation in the early universe. One in particular (https://arxiv.org/abs/1803.04527) even varies ...
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How could a supernova seed solar nebula?

If the heavier elements such as Uranium came from a supernova, then this supernova had to sit somewhere right in the middle of the original solar nebula, because although the ejected matter traveled ...
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Why does star formation cease?

The universe is expected to have a time when star formation slowly ceases. However, this seems bizarre as there is always an abundant amount of matter in the Universe. Massive amounts of hydrogen ...
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Stellar nurseries in the “Shedding New Light on the Whirlpool Galaxy” video

Captions in the Hubble Space Telescope YouTube channel video Shedding New Light on the Whirlpool Galaxy say: (visible) Along the dark dust lanes, bright pink nebulae are the birthplace of new stars....
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Could stars form outside of galaxies?

Is it possible for there to be a dense enough nebula to form stars outside of any galaxy? Does a galaxy have a minimum size to produce stars? Or could you have a few dozen stars clustered together by ...
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Activity of M dwarf stars

Why are M dwarf stars the most active (in terms of starspots and faculae) of all stars?
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A few questions regarding the transit of planets

Here we will be concerning ourselves with the transit of a planet with it's parent sun. I have a few questions that I am not sure about: 1) Do all planets transit their parent sun? It would seem to ...
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Remains of the progenitor of the Sun

It has been argued that it is not possible to trace back the remains of the progenitor star of the Sun (sometimes called Coatlicue), which, being estimated in the mass range of 30 $M_{\odot}$, should ...
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Can a donut-shape planet or star be formed?

How stable is that configuration and under what conditions such object may form ? Is there any evidence suggesting that such objects might exist ?
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Is there any definitive proof of stars being “born” in nebula formations?

Is there any absolute evidence of star formation inside of nebulae (AKA stellar nurseries) as is suggested and even stated as fact by many textbooks?
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The formation of new stars as depicted in Feynman's lectures

I've stumbled upon this curious passage addressing the formation of stars in Feynman's lectures on physics: Whether we have ever seen a star form or not is still debatable. Figure 7–12 shows the ...
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What does the ']' in the spectral line “CIII] 1909 Å” mean?

The above emission line, as I understand, is a useful probe of early star-forming galaxies. However, I do not understand what the ']' to the right of the 'CIII' means. I could not find any online ...
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Black-hole becoming a star again - follow-up question [closed]

Some questions have been posed about black holes becoming stars again once they attract enough hydrogen/atomic matter from another star. Some answers were a forceful NO. Never. However - let's ponder ...
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What's the profound reason(s) why the star formation rate drives the scatter of the mass-metallicity relation in galaxies?

Since decades it's well known that a correlation between stellar mass and metallicity (Z; both stellar and gas-phase Z, but here I focus on the gas-phase Z) exists (e.g., Tremonti+04; analysis of >...
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Black Dwarf Capabilities

Can a black dwarf be suitable for manned exploration, once it cools down? And potentially used for space mining?
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Star formation around rotating black holes?

Please excuse an amateur question. While trying to think of anything but what was happening during a dental procedure my mind turned to a model of a star close to a rotating black hole and the ...
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Doubt about star formation [duplicate]

When a star runs out of hydrogen, it either goes through supernova or forms white dwarf and planetary nebula. So there should not be much hydrogen left to form a new star in the nebula. So how new ...
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If two white dwarfs collided, would they become a star?

Would the temperatures during such a collision be able to ignite nuclear fusion, bringing the dead star back to life? If so, would it only be able to fuse for a short time before running out of fuel, ...
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Will all of the gas in the universe be converted into red dwarf stars?

Red dwarfs have lifespans of trillions of years and are also the most abundant stars, making up 70% of the stars in the Milky Way. No red dwarf star has ever died and none will die for a very, very ...
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How did the lighter elements end up in the center of the solar system? Solar System Formation

The previous generation of stars famously are the origin of all the heavier elements (up until iron?) in the solar system. So a big portion of the solar system mass actually is made up of Carbon, ...
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If two binary brown dwarfs began to exchange gas with each other, would they both ignite into stars?

If two brown dwarfs got close enough to exchange gas with each other, could it trigger nuclear fusion within their cores? Is it possible for two brown dwarfs to orbit so closely and become a ...
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Term for the moment when hydrogen fusion begins in a star

I have read of this process many times, but I don't think I know the term specifically for the moment when hydrogen fusion begins. What is this moment called?
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How was the Sun formed?

Refer to the below minutephysics video, in which they say that in order to reach the Sun from earth, we must first stop revolving around the Sun ie make our tangential velocity zero, and then head ...
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What are infall signatures in stars?

I came across several papers (e.g. Looking for outflow and infall signatures in high mass star forming regions P. D. Klaassen, L. Testi and H. Beuther, 2011) talking about infall signatures in star ...
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How do we calculate heat flow or cooling rate for no fusion brown dwarf star?

I was reading this article and it said something that didn't sit right with me. "SIMP0136 still gives off light mostly in the infrared wavelengths, as its temperature is now approximately 830° C (1,...
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Spacing of G and K class stars

I was looking at the Wikipedia article "List of potentially habitable exoplanets" and I noticed that many of the closest planets listed(tens or hundreds instead of thousands of light-years away) ...
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What are IRAS sources?

Do IRAS sources refer to star forming regions? I searched google and I came to know that it stands for IR astronomical satellite.But what do they search for? Please help me
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How long will star formation endure before the eventual heat death of the observable universe?

Lord Kelvin's prediction of heat death indicates the eventual end to star formation in the observable universe. Have any astrophysicists made any predictions for the endurance of star formation in the ...
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How are binary star systems created?

I don't know how common it is for a system to have two stars (or perhaps even more) but how do they arise? Is that due to the stellar accretion disc, or the composition of the stellar nebula? Or are ...
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How were the first stars formed?

In class, we read a Scientific American article, "Cloudy with a Chance of Stars" that explained how the cores and the dust around them formed stars(he called them eggs for a chicken/egg analogy, where ...
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Looking for Galactic Data

I am doing some personal research and just and am trying to find a decent source for galactic data. Specifically I am looking for a database that includes the estimated size of the galaxy's ...
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Sky in the very far future / past

Motivated by this question about a stranded submarine in the Jurassic I would like to know: Is there anything remotely left of our current skyline if we go back or forward millions of years so that ...
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What characteristics or patterns do galaxies have on color-luminosity chart? [closed]

For the following graph, I have some confusions: How do galaxies rank by mass? We know that on main-sequence, more luminous stars are also more massive, so I guess it also applies to galaxies. Do red ...
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654 views

How do we know a star's age based on its spectrum? [duplicate]

A star's nearby environment may give clue to its age. Different stellar type have different spectral features. If we just have its spectrum, how do we know its age? For example, a star may be born ...
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I have some questions about star formation [closed]

Q2 What does the phrase 'containing several distinct knots of collopsing material' mean? Q3 In this context, does the word 'such clouds' mean protostar? (I'm not an English-native speaker.) Q4 In ...
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Sun's formation as “part of a star-forming-cluster…”?

After reading this interesting answer, I was wondering, do we in fact know if our Sun in particular was created as part of a star-forming-cluster, or, was it more of a solo creation? (Or, are all ...
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What is the origin of the dust near the sun?

In this question I asked about the Solar Probe Plus mission. Reading a 2008 report I saw that there is an elevated exposure to high velocity dust near the sun. I understand the high velocity, anything ...
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Could the earth become a star if more mass was added?

I've heard that the only difference between a star and a planet is mass, meaning that if planets accredited enough mass they would too become stars. Does this mean that the star started off as a ...
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Star formation: When a nebula collapses, is it only the gasses that form the star?

A nebula is made of dust (elements heavier than He and H) and gas (H and He). Stars are made when nebulae's collapse and hydrogen begins to fuse. 99% of nebula material goes into making the star. The ...
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How to show that the Jeans Criterion for Mass, Radius and Density are equivalent?

The gravitational collapse of a gas cloud can be described by the Jeans Criterion for mass, radius and density of the gas cloud, which is (c stands for cloud): $$M_J = (\frac{5kT}{G \mu m_H})^{3/2} (...
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Luminosity L(t) for a homologously contracting star

I'm dealing with a homologously contracting star with Mass M, Radius R and a gravitational binding energy of $E = -a GM^2 / R $ (a is a constant). I was looking for a way to find an expression ...
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How can we explain high redshift numbers?

I just finished an introductory astrophysics course$^1$ and I have a lingering question that I can't seem to resolve. We learned that for the first few hundred million years, the universe was pretty ...
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Why dust is optically thin in Far Infrared wavelengths?

What is the actual meaning of the statement 'Dust is optically thin in the Far Infrared (FIR) over most of the Galaxy'? Kindly Help
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What does “EW(Hα)” mean?

I came across a website saying that classical T Tauris have an "EW(Hα) > 5 angstroms". Does anybody know what "EW" means? Thanks.
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How can ionized emission line flux decrease as a function of increasing metallicity or abundance?

The chemical evolution of galaxies is an important way to learn about their formation and stellar/gaseous constituents. Many galaxies show narrow emission lines at optical wavelengths (3500-9000 ...
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If a star were to suddenly lose nearly all of its stored heat, would it be able to return to its normal state? [closed]

If not, would it be possible to approximate the maximum heat energy a star could lose before the change became irreversible?
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Are there any hot jupiters orbiting red dwarfs?

Do we know of any hot jupiters that could be orbiting a red dwarf (or, more probably, orbiting a barycenter between the two)? Is this scenario even physically possible?